Fire-brick.



clay and flint clay or silica sands.

UNITED STATES PATENT oFFioE- CARVER HIDECKER, OF;

sanransnnm camronma AssIGNoaTo IONE FIRE BRICK- coMPAnY oFHsA .EBANGISCQL-CALIFORNIAWA CORPORATION or. CALIFORNIA.

FIRE-BRICK.

No Drawing;

boxes for use with coal are lined with clayv linings made in molds and burnt sufliciently to hold their form. These linings are adapted to withstand a heat not exceeding a smoking temperature, that is, at which the heat is not suflicient to prevent the for- 'mation of smoke. They are composed of flint clays or silica sands together with plastic or potter clays. The flint clays and silica sands fuse only at high temperatures, and the plastic clays, which are used merely to bind said clays, or sands in the forms or bricks, fuse at somewhat lower temperatures. These materials are properly mixed, and a brick formed of the mixture is raised to a temperature between the fusing points of plastic When allowed to cool, it contracts, and becomes a dense granular mass, and being less porous it possesses a greater resistance than before to the passage of heat. Such a brick when exposed to very great heat is destroyed in the following manner. Heat applied to the exterior of the brick travels along its pores, causing an expansion of the mass, so that the granules in the brick are more accessible to the heat and can to a less degree withstand its action, which therefore'proceeds with increased efiect, until finally complete disintegration takes place.

As municipal smoke ordinances for the prevention of smoke emission have been put into effect, it has been learned that the prevention of smoke can, in practice, only be secured by preventing its original formation. This can only be done by using very high temperatures in the furnace. As these temperatures are at least 1,000 F. higher than the smoking temperature heretofore used, there is a demand for a brick that will resist heat of such high temperatures. Only in a measure has the demand been met. This has been done principally, so far as I am aware, by applying to the surface of the bricks after they are. set in furnaces certain Specification of Letters Patent.

Patented Oct. 27, 1914.

Applicatiorb'filed. me 3, 1913. Serial No. 771,537;

cements, fusible only at a high temperature. The oiiice' of these cements is to close the porosity of the granular-mass brick on its surface by a-material which will-fuse only at a high heat, saidcement thus furnishing a very great obstruction to the transmission of the heat into the brick,-both by; closing the pores in the brick through which the heat might the more easily-penetrate and also by providing a surface material which cannot readily be .removedby fllSlOIL- However there are two principal objections to a brick of this character; first, if the surface be comes fractured its efficiency is lost; second, the cost of applying these cements doubles the cost of the granular-mass brick.

I propose to produce a fire brick which has the combined advantages of the granular-mass brick and the high-temperature cement and at an increase in the cost of only- 30 per cent. of the increase by said use of cement. In this brick I propose to use 75 per cent. of non-contracting refractory material, as flint clay, or silica sands, fusing only at a temperature of 2800 F., 10 per cent. of plastic clay, contracting from its original condition after being fused, and fusing at a temperature of 2,500 F., 10 per cent. of shale fusing at 2250 F. and 5 per cent. of practically infusible material, by which is meant one which does not fuse at a temperature below 4,000 F.

A brick of the above materials is made by burning in a kiln ata heat of not less than 2800 F. When cooled from such a temperature it will shrink or be compacted, but it can never again be fused by a furnace heat of less than 3500 F. This result is due to the employment of a practically infusible material combined with a pore-filling material, which practically infusible material offers so great resistance to the passage of heat through the more easily fusible material that the brick cannot become fused at a less temperature than above stated.

Furnace bricks are destroyed by absorption of heat through the pores more readily than through the external surface of the brick. The reason for this is that the external. surface of the brick is very small compared with its internal surface around the pores. Hence, if the pores of the brick be filled by a substance whichv cannot be readily fused, it follows that the brick can only absorb heat through the external surface. The practically infusible material used in the brick is a product of the electric furnace, one such substance being carborundum.. I do not confine myself to any special substance but claim the invention using any practicallyinfusible material.

It will readily be understood from the foregoingdescription that it is important to proportion the relative sizes of the several materials. The fiint clay or silica. sands are used in comparatively large particles, while the pore-filling material and the practically non-fusible'material are in very fine particles, the object of the latter two being to fill up thevoids made by the large particles 1 of refractory material. Furthermore the percentage of the ingredients above described will vary in amounts according to theirvpurlty or condition as found in nature.

CARVER HIDECKER.

Witnesses:

FRANCIS M. WRIGHT, D. B. RICHARDS. 

